Scotland lost a difficult opening game 57-5 to last years IRB Sevens World Series champions Fiji. Scotland's only try came from Ben Addison.
However, the Scots brought themselves back in the hunt for a quarter-final place with a memorable 19-14 win over Argentina 7s.
The result, which saw tries from Thom Evans, Ben Addison and Sean Crombie, elated head coach Stephen Gemmell.
"It was a great win but they scored two late tries just before the end which we shouldn't have allowed.
"A win against the West Indies should secure us a vital quarter-final place for tomorrow."
Mike Adamson converted two of Scotland's three tries.